Monochrome Multiplex Quantitative Polymerase Chain Research Articles

Maternal peripheral blood telomere length and preterm birth in African American women: a pilot study.

This study aimed to explore the association between preterm birth and telomere length of maternal peripheral blood in African American women. 78 African American women were recruited for this study between 2018 and 2023 from 2 prenatal clinics in central and east Texas. Participants provided blood samples and completed clinic questionnaires, with clinical data collected from their post-delivery medical records. Telomere length was measured using monochrome multiplex quantitative real-time polymerase chain reaction. Linear regression and multinomial logistic regression were used to analyze the association between telomere length and gestational length. Kruskal-Wallis's test and Fisher's exact test were used to compare preterm birth, early-term birth and full-term birth by telomere length, social-demographic characteristics, stress and discrimination. The rates of preterm birth was higher in pregnant women with shorter telomeres. After adjusting for confounders, for every 10-units increase in the relative telomere-to-single-copy gene (T/S) ratio, gestational days increased by 1.090 days (90% CI 0.182, 1.997), and for every 10-units decrease in the T/S ratio, the odds of preterm birth was 2.664 (90% CI 1.064, 6.673) times greater than the odds of full-term birth. No statistically significant associations were observed between stress, discrimination, and either preterm birth or telomere length. Maternal peripheral blood telomere shortening is associated with preterm birth, providing support to further explore the clinical utility of maternal telomere testing for prediction and early intervention of preterm birth and the study of biological mechanisms of spontaneous preterm birth.

Monochrome Multiplex Quantitative PCR Telomere Length Measurement.

Telomeres are ribonucleoprotein structures at the end of all eukaryotic chromosomes that protect DNA from damage and preserve chromosome stability. Telomere length (TL) has been associated with various exposures, biological processes, and health outcomes. This article describes the monochrome multiplex quantitative polymerase chain reaction (MMqPCR) assay protocol routinely conducted in our laboratory for measuring relative mean TL from human DNA. There are several different PCR-based TL measurement methods, but the specific protocol for the MMqPCR method presented in this publication is repeatable, efficient, cost-effective, and suitablefor population-based studies. This detailed protocol outlines all information necessary for investigators to establish this assay in their laboratory. In addition, this protocol provides specific steps to increase the reproducibility of TL measurement by this assay, defined by the intraclass correlation coefficient (ICC) across repeated measurements of the same sample. The ICC is a critical factor in evaluating expected power for a specific study population; as such, reporting cohort-specific ICCs for any TL assay is a necessary step to enhance the overall rigor of population-based studies of TL. Example results utilizing DNA samples extracted from peripheral blood mononuclear cells demonstrate the feasibility of generating highly repeatable TL data using this MMqPCR protocol.

Abstract 2255: Alu retroelement copy number alterations and non-Hodgkin lymphoma

Abstract Background: Alu retrotransposons are repetitive DNA elements that make up nearly 10% of the human genome and reflect genomic instability. Genomic instability plays an important role in the pathogenesis of non-Hodgkin lymphoma (NHL). However, the relationship between Alu retrotransposons and future risk of NHL is unclear. Methods: We conducted a nested case-control study of NHL risk and Alu retroelement copy number within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) study, a prospective cohort with prediagnostic blood samples from 29,133 male Finnish smokers. We measured Alu copy number in 107 incident NHL cases and 1:1 matched controls (± 5 years age). DNA samples extracted from blood were assayed in triplicate using a monochrome multiplex quantitative polymerase chain reaction. We used the albumin gene for the single copy gene to control for genome content in samples. The odds ratios (OR) and 95% confidence intervals (CI) for all NHL were estimated using conditional logistic regression models, adjusting for age at randomization, number of cigarettes smoked per day and smoking duration. Polytomous logistic regression models were fit to compute ORs with Alu copy number for NHL subtypes. To determine if the association might be driven in part by elevated Alu copy number among undiagnosed cases at the time of blood sample collection, we excluded cases diagnosed within the first two years of follow-up. Results: Higher Alu copy number (using the median as the cut-point) was associated with an increased risk of NHL, both overall [OR, 95% CI=3.80 (1.76-8.17)] as well as for the diffuse large B-cell lymphoma [OR, 95% CI=4.83 (1.50-15.55)] and chronic lymphocytic leukemia/small lymphocytic lymphoma (SLL) [OR, 95% CI=2.66 (1.10-6.40)] subtypes. These associations were similar after excluding individuals diagnosed with NHL within two years after blood draw. Conclusions: These findings, which require replication, suggest that higher Alu copy number in prediagnostic leukocytes may play a role in the pathogenesis of NHL. Citation Format: Wei Hu. Alu retroelement copy number alterations and non-Hodgkin lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2255.

Daily Oral Supplementation with 60 mg of Elemental Iron for 12 Weeks Alters Blood Mitochondrial DNA Content, but Not Leukocyte Telomere Length in Cambodian Women.

There is limited evidence regarding the potential risk of untargeted iron supplementation, especially among individuals who are iron-replete or have genetic hemoglobinopathies. Excess iron exposure can increase the production of reactive oxygen species, which can lead to cellular damage. We evaluated the effect of daily oral supplementation on relative leukocyte telomere length (rLTL) and blood mitochondrial DNA (mtDNA) content in non-pregnant Cambodian women (18–45 years) who received 60 mg of elemental iron as ferrous sulfate (n = 190) or a placebo (n = 186) for 12 weeks. Buffy coat rLTL and mtDNA content were quantified by monochrome multiplex quantitative polymerase chain reaction. Generalized linear mixed-effects models were used to predict the absolute and percent change in rLTL and mtDNA content after 12 weeks. Iron supplementation was not associated with an absolute or percent change in rLTL after 12 weeks compared with placebo (ß-coefficient: −0.04 [95% CI: −0.16, 0.08]; p = 0.50 and ß-coefficient: −0.96 [95% CI: −2.69, 0.77]; p = 0.28, respectively). However, iron supplementation was associated with a smaller absolute and percent increase in mtDNA content after 12 weeks compared with placebo (ß-coefficient: −11 [95% CI: −20, −2]; p = 0.02 and ß-coefficient: −11 [95% CI: −20, −1]; p= 0.02, respectively). Thus, daily oral iron supplementation for 12 weeks was associated with altered mitochondrial homeostasis in our study sample. More research is needed to understand the risk of iron exposure and the biological consequences of altered mitochondrial homeostasis in order to inform the safety of the current global supplementation policy.

Telomere dynamics across the early life course: Findings from a longitudinal study in children

Telomeres are protective caps on chromosome ends that shorten with each cell division. Telomere length (TL) predicts the onset of cellular senescence and correlates with longevity and age-related disease risk. Previous research suggests that adults display fixed ranking and tracking of TL by age 20 years, supporting the importance of TL at birth and attrition during childhood. However, longitudinal research examining telomere dynamics during early life is sparse. Here, we used monochrome multiplex quantitative polymerase chain reaction to measure relative TL in leukocytes isolated from cord blood and child blood collected at ages 3, 5, 7, and 9 years among 224 minority children enrolled in a New York City-based birth cohort. We also measured maternal TL at delivery in a subset of 197 participants with a biobanked blood sample. TL decreased most rapidly in the first years of life (birth to 3 years), followed by a period of maintenance into the pre-puberty period. Mothers with longer telomeres gave birth to newborns with longer telomeres that remained longer across childhood, suggesting that the fixed ranking and tracking of TL observed among adults may extend to early childhood or even the prenatal period with a potential transgenerational basis. We did not find significant sex differences in the pattern of child TL change across development. These findings emphasize the need to understand factors and mechanisms that determine TL during early childhood.

The correlation of salivary telomere length and single nucleotide polymorphisms of the ADIPOQ, SIRT1 and FOXO3A genes with lifestyle-related diseases in a Japanese population.

It has been reported that genetic factors are associated with risk factors and onset of lifestyle-related diseases, but this finding is still the subject of much debate. The aim of the present study was to investigate the correlation of genetic factors, including salivary telomere length and three single nucleotide polymorphisms (SNPs) that may influence lifestyle-related diseases, with lifestyle-related diseases themselves. In one year at a single facility, relative telomere length and SNPs were determined by using monochrome multiplex quantitative polymerase chain reaction and TaqMan SNP Genotyping Assays, respectively, and were compared with lifestyle-related diseases in 120 Japanese individuals near our university. In men and all participants, age was inversely correlated with relative telomere length with respective p values of 0.049 and 0.034. In men, the frequency of hypertension was significantly higher in the short relative telomere length group than in the long group with unadjusted p value of 0.039, and the difference in the frequency of hypertension between the two groups was of borderline statistical significance after adjustment for age (p = 0.057). Furthermore, in men and all participants, the sum of the number of affected lifestyle-related diseases, including hypertension, was significantly higher in the short relative telomere length group than in the long group, with p values of 0.004 and 0.029, respectively. For ADIPOQ rs1501299, men's ankle brachial index was higher in the T/T genotype than in the G/G and G/T genotypes, with p values of 0.001 and 0.000, respectively. For SIRT1 rs7895833, men's body mass index and waist circumference and all participants' brachial-ankle pulse wave velocity were higher in the A/G genotype than in the G/G genotype, with respective p values of 0.048, 0.032 and 0.035. For FOXO3A rs2802292, women's body temperature and all participants' saturation of peripheral oxygen were lower in the G/T genotype than in the T/T genotype, with respective p values of 0.039 and 0.032. However, relative telomere length was not associated with physiological or anthropometric measurements except for height in men (p = 0.016). ADIPOQ rs1501299 in men, but not the other two SNPs, was significantly associated with the sum of the number of affected lifestyle-related diseases (p = 0.013), by genotype. For each SNPs, there was no significant difference in the frequency of hypertension or relative telomere length by genotype. Relative telomere length and the three types of SNPs determined using saliva have been shown to be differentially associated with onset of and measured risk factors for lifestyle-related diseases consisting mainly of cardiovascular diseases and cancer.

Telomere length in peripheral blood lymphocytes related to genetic variation in telomerase, prognosis and clinicopathological features in breast cancer patients.

Disruption of telomere length (TL) homeostasis in peripheral blood lymphocytes has been previously assessed as a potential biomarker of breast cancer (BC) risk. The present study addressed the relationship between lymphocyte TL (LTL), prognosis and clinicopathological features in the BC patients since these associations are insufficiently explored at present. LTL was measured in 611 BC patients and 154 healthy controls using the monochrome multiplex quantitative Polymerase Chain Reaction assay. In addition, we genotyped nine TL-associated single-nucleotide polymorphisms that had been identified through genome-wide association studies. Our results showed that the patients had significantly (P = 0.001, Mann-Whitney U-test) longer LTL [median (interquartile range); 1.48 (1.22-1.78)] than the healthy controls [1.27 (0.97-1.82)]. Patients homozygous (CC) for the common allele of hTERT rs2736108 or the variant allele (CC) of hTERC rs16847897 had longer LTL. The latter association remained statistically significant in the recessive genetic model after the Bonferroni correction (P = 0.004, Wilcoxon two-sample test). We observed no association between LTL and overall survival or relapse-free survival of the patients. LTL did not correlate with cancer staging based on Union for International Cancer Control (UICC), The tumor node metastasis (TNM) staging system classification, tumour grade or molecular BC subtypes. Overall, we observed an association between long LTL and BC disease and an association of the hTERC rs16847897 CC genotype with increased LTL. However, no association between LTL, clinicopathological features and survival of the patients was found.

Довжина теломер у хворих на цукровий діабет 2-го типу та її зв’язок із метаболічним профілем

To study leukocyte telomere length and its relationship with metabolic profile 35 patients with metabolic syndrome and type 2 diabetes mellitus (T2DM) and 21 healthy people of middle age (35-59 years) were examined. The anthropometric characteristics of obesity, indicators of lipid and glucose metabolism, alanin aminotransferase (ALT) and high sensitive C-reactive protein levels were studied. The relative average telomere length was determined by the method of monochrome multiplex quantitative real time polymerase chain reaction. Patients with T2DM had higher BMI, waist circumference, higher high sensitive C-reactive protein, ALT and glucose levels and a worse lipid profile (p <0.05). At the same time, the median telomere length did not differ between groups. Nevertheless, in the T2DM group the telomere length inversely correlated with body weight (r = –0.35; p < 0.05), BMI (r = –0.36; p < 0.05), waist circumference (r = –0.34; p < 0.05) and ALT level (r = –0,44; p<0,05) in contrast to healthy subjects. No relationship was found between the telomere length and the level of fasting glycemia, as well as the age of the participants of both groups. Thus, in T2DM patients increase in BMI, waist circumference and ALT level were associated with a shorter leukocyte telomere length. Despite the worse metabolic profile, the telomere length in middle-aged T2DM patients did not differ from that in the control group. This indicates that the leukocyte telomere length is influenced not only by the presence of T2DM and the metabolic profile indicators, but, obviously, by other factors as well.

Childhood obesity and leucocyte telomere length.

Obesity in adulthood is associated with decreased leucocyte telomere length (LTL), which is associated with cardiovascular disease and diabetes mellitus type 2. The aim of our study was to investigate whether increased body mass index (BMI) is associated with decreased LTL in children and adolescents, and to identify other risk factors of shorter LTL in this population. A cross-sectional study was conducted among 919 Greek children aged 9-13years (The Healthy Growth Study). Participants were classified as obese (n=124), overweight (n=276) or of normal BMI (n=519). LTL was determined by monochrome multiplex quantitative real-time polymerase chain reaction. Univariate and multivariable linear regression analyses were applied to determine the predictive factors of LTL. Both overweight and obese children had significantly shorter LTL than their normal-BMI counterparts. Following adjustment for age, sex, total daily energy intake and average weekly physical activity (average total steps per day), increasing weight category was inversely associated with LTL in children and adolescents (β: -0.110±0.035; P=.002). Overweight and obesity in childhood and adolescence are associated with shorter LTL, even following adjustment for potential confounding effects. Therefore, the increased BMI in childhood and adolescence may be associated with accelerated biological ageing and may have an adverse impact on future health in adulthood.

Association between leukocyte telomere length and the risk of pancreatic cancer: Findings from a prospective study

IntroductionTelomeres and telomerase play important role in maintaining chromosome integrity and genomic stability. Recent epidemiologic data showed inconsistent findings which suggested that both short and long leukocyte telomeres could be associated with increased risk of pancreatic cancer. We prospectively examined the association between telomere length and pancreatic cancer risk in a population-based cohort study.MethodsThe Singapore Chinese Health Study recruited 63,257 Chinese aged 45 to 74 years from 1993 to 1998 in Singapore. Relative telomere length in peripheral blood leukocytes was quantified using a validated monochrome multiplex quantitative polymerase chain reaction method in 26,540 participants, including 116 participants who later developed pancreatic cancer after an average of 13 years of follow-up. Cox proportional hazard regression method was used to calculate hazard ratio (HR) and its 95% confidence interval (CI) of pancreatic cancer risk associated with telomere length, with adjustment for confounding factors.ResultsLonger telomeres were significantly associated with higher risk of pancreatic cancer (Ptrend = 0.02). Compared with lowest quartile, subjects with highest quartile of telomere length had an HR of 2.18 (95% CI: 1.25–3.80) for developing pancreatic cancer. In stratified analysis, this association remained among pancreatic adenocarcinoma patients but not among pancreatic non-adenocarcinoma patients. In continuous scale, the HRs and 95% CIs were 3.08 (1.17–8.11) for adenocarcinoma patients and 1.47 (0.43–5.06) for non-adenocarcinoma patients. The HRs and 95% CIs of the highest quartile of telomere length, compared with the lowest quartile, for adenocarcinoma and non-adenocarcinoma were 2.50 (1.22–5.13) and 1.63 (0.66–4.03), respectively. The length of follow-up from the collection of blood for the measurement of telomere length to the diagnosis of cancer (median = 8.0, range: from 5.0 months to 16.2 years) had no significant impact on the association between telomere length and pancreatic cancer risk.ConclusionsThe present study demonstrates that longer telomeres are associated with increased risk of overall pancreatic cancer.

PS1171 TELOMERE LENGTH AT DIAGNOSIS OF CHRONIC MYELOID LEUKEMIA PREDICTS THE ACHIEVEMENT OF DEEP MOLECULAR RESPONSE TO IMATINIB

Background:Telomere length (TL) is shortened with every cell division. Critically short telomeres are associated with genetic instability. In chronic myeloid leukemia (CML), increased cellular turnover of clonal BCR‐ABL1‐positive hematopoietic stem and progenitor cells leads to significantly shortened telomeres in myeloid cells from peripheral blood (PB). Retrospective studies have related accelerated telomere shortening in CML to disease stage, clinical risk score at diagnosis as well as cytogenetic remission.So far, no study has considered the possible association between TL at diagnosis of CML and the achievement of deep molecular response (DMR) with imatinib (IM) treatment.Aims:To explore if TL at diagnosis of CML is predictive of DMR achievement with IM as first‐line treatment.Methods:Samples from 100 patients with de novo CML at diagnosis of three different Catalan hospitals between 2004 and 2016 were included. Three patients were considered as missing due to no valid PCR results. All patients provided informed consent. Patients’ median age was 49 yrs (range 24–80 yrs) and 59% were males. Thirty‐one (38%) patients had the e13a2 p210 BCR‐ABL1 isoform whereas 51 (62%) had the e14a2 isoform. According to Sokal and ELTS scores, 48(50%) and 52(60%) patients were low risk, 30(32%) and 24(28%) were intermediate risk while 17(18%) and 10(12%) were high risk, respectively.Patients were treated with first line IM 400 mg QD orally. For the molecular response (MR) analysis, only response to IM was considered. Response during the first year was assessed according to European Leukemia Net 2013 guidelines. DMR was defined as MR4.0 or MR4.5 The median time from IM start to MR4.0 achievement was 16.1 months (5.5, 100.7). Follow‐up was at least 24 months for all patients.For TL determination, DNA was extracted from PB or bone marrow cells. TL was analysed by monochrome multiplex quantitative polymerase chain reaction and the results were expressed as the standardized T/S ratio. Age adaptation of TL, indicated as ΔTL (delta‐TL), was performed using data from 107 healthy controls (age range 16–84 years). The ΔTL for every patient was calculated subtracting the subject's linear predicted TL (linear regression analysis of healthy controls) from the observed TL.Results:Healthy controls showed the expected decline in TL with increasing age (R2 = 0.1693), which was not detectable in CML (R2 = 0.0002), suggesting that telomeres are not age‐dependent in CML at diagnosis.Analysing the clinical data, no significant correlation between ΔTL and clinical prognostic scores (Sokal and ELTS, with p = 0.816 and p = 0.314, respectively) was observed, nor between ΔTL and p210 BCR‐ABL1 onco‐protein isoforms (e13a2 and e14a2, p = 0.981).Finally, focusing on the ΔTL representing the difference between TL expected by age and TL determined in the CML cells, patients with lower ΔTL at diagnosis were significant associated with achievement of MR4.0 and MR4.5 (HR [95%CI]: 0.24 [0.1, 0.74], p = 0.013 and 0.23 (0.1, 0.76), p = 0.016, respectively). In addition, when patients were stratified according to median value of ΔTL (0.40), those with ΔTL<0.40 significantly achieved MR4.0 earlier than patients with ΔTL>0.40 (median in months [95%CI]: 21 [8.2, 33.7] vs 46.2 [23.6, 68.8], p = 0.034) (Fig1).Summary/Conclusion:TL at diagnosis of CML is a predictive biomarker of DMR achievement with IM as first‐line treatment. Acknowledgements: FIS (AES 2016) PI16/01200 and FEHH.image

Comparison of Fluorescence in Situ Hybridization and Flow Cytometry (Flow-FISH) with Monochrome Multiplex Quantitative Polymerase Chain Reaction (MM-qPCR) for Telomere Length Screening in Adult Patients with Suspected Cryptic Dyskeratosis Congenita (DKC)

Introduction: Dyskeratosis Congenita (DKC) is caused by defective telomere maintenance, mostly due to mutations impacting on the functional activity of telomerase. Classical DKC is characterized by mucocutaneous features and bone marrow failure diagnosed during childhood. In contrast, the cryptic form of DKC often first manifests itself in adulthood and presents clinically with less characteristic manifestations. Correct identification of DKC patients is of utmost importance because of significant implications for the affected patients (treatment, toxicities) and her/his family (donor selection, genetic counselling). Accelerated shortening of telomere length (TL) in peripheral blood leucocytes (PBL) represents the functional read-out and consequently, clinically useful screening parameter of altered telomere function. Consequently, in cases without distinct genetics or clinical presentation, significantly shortened TL is frequently used as a disease-defining marker. TL in PBL of pediatric DKC patients typically is below the first percentile (<1%). However, the difference between the normal range and critically short telomeres decreases with age, thus complicating the diagnosis of DKC in adult patients. Consequently, the TL threshold below 10% of age-adjusted healthy controls is frequently recommended in adults. Currently, fluorescence in situ hybridization and flow cytometry (Flow-FISH), especially of the lymphocyte subpopulation, or monochrome multiplex quantitative polymerase chain reaction (MM-qPCR) are preferred techniques for TL assessment. In our study, we compared MM-qPCR to Flow-FISH regarding their ability to properly identify DKC patients.Methods and Patients: 105 patients enrolled in the Aachen Telomeropathy Registry from 2015 to 2017 were analysed. Patient inclusion criteria were based on the clinical suspicion of cryptic DKC by the treating physician. Patient's median age was 47.5 [range 2-88] years. Initial diagnoses were aplastic anemia/paroxysmal nocturnal hemoglobinuria (n=50), unexplained cytopenia (n=20), genetically confirmed DKC mutation/polymorphism or screening of family members (n=14) as well as other disorders (e.g. lung fibrosis, n=21). All patients underwent customized amplicon-based next-generation sequencing analysis (TERT, TERC, DKC1, NOP10, NHP2, USB1, CTC1, RTEL1, TIN2, TCAB1) on a Miseq sequencer. 16/105 patients were identified with a known DKC-related mutation (TERC n=6, TERT n=6, RTEL1 n=3, DKC1 n=1). Median age of the DKC patient cohort was 44.5 (range 21-77) years. Age adaption was performed by using healthy control and TL assessment of PB granulocytes and lymphocytes was carried out in parallel by Flow-FISH and MM-qPCR with all experimental samples assayed in triplicatesResults: We observed that TL measured by MM-qPCR correlates with lymphocyte and granulocyte TL measured by flow-FISH (R²=0.33 and R²=0.25, respectively; both p≤0.001). Assessment of lymphocyte TL by Flow-FISH led to values below the 1% or 10% threshold of normal individuals in 24% (n=26) or 49% (n=51) of the patients, respectively leading to a detection rate of 75% (n=12) or 88% (n=14) of the known DKC patients. In comparison, TL assessment by MM-qPCR resulted in 29% (n=31) or 74% (n=78) of the patients below the 1% or 10% percentile, respectively leading to a detection rate of known DKC cases of 68% (n=11) or 94% (n=15). Thus, the sensitivity of both techniques basically did not differ. When we used the 1% cut off, the specificity of flow-FISH (84%, n=75/89) and MM-qPCR (78%, n=69/89) again did not differ significantly (p=0.74). However, using the 10% threshold, specificity of MM-qPCR (29%, n=26/89) was significantly lower compared to flow-FISH (58%, n=52/89, p=0.02). Finally, the rate of false positive patients using flow-FISH was 13% (n=14) and 19% (n=20) for MM-qPCR for the 1% threshold. Using the 10% threshold, we observed a significantly higher rate of false positive patients using MM-qPCR with 60% (n=63/105) compared to Flow-FISH with 35% (n=37/105, p=0.04).Conclusions: Depending on the applied threshold, the use of MM-qPCR as a screening and confirmatory method for telomere maintenance disorders was inferior in specificity and showed a significant higher rate of false positive results compared to flow-FISH. Our results suggest the use of flow FISH as the gold standard method of screening especially in adults with suspected cryptic DKC. DisclosuresKirschner:Basilea Pharmaceutica: Other: travel support; BMS: Consultancy; Roche: Consultancy; Bayer: Consultancy. Wilop:Medizinwelten-Services GmbH: Honoraria; Amgen: Consultancy; Celgene: Consultancy, Honoraria, Other: Travel grant; Bristol-Myers Squibb: Honoraria. Brümmendorf:Novartis: Consultancy, Research Funding; Merck: Consultancy; Janssen: Consultancy; Takeda: Consultancy; Pfizer: Consultancy, Research Funding. Beier:Celgene: Other: travel support; Gilead: Other: travel support.

Leukocyte telomere length in relation to risk of lung adenocarcinoma incidence: Findings from the Singapore Chinese Health Study.

Telomeres are crucial in the maintenance of chromosome integrity and genomic stability. Critically short telomeres can trigger programed cell death while cells with longer telomeres may have increased likelihood of replicative errors, resulting in genetic mutations and chromosomal alterations, and ultimately promoting oncogenesis. Data on telomere length and lung cancer risk from large prospective cohort studies are spare. Relative telomere length in peripheral blood leukocytes was quantified using a validated monochrome multiplex quantitative polymerase chain reaction (qPCR) method in 26,540 participants of the Singapore Chinese Health Study. After a follow-up of 12 years, 654 participants developed lung cancer including 288 adenocarcinoma, 113 squamous cell carcinoma and 253 other/unknown histological type. The Cox proportional hazard regression was used to estimate hazard ratio (HR) and 95% confidence interval (CI). HR of lung adenocarcinoma for individuals in the highest comparing the lowest 20 percentile of telomere length was 2.84 (95% CI 1.94-4.14, ptrend < 0.0001). This positive association was present in never smokers (ptrend < 0.0001), ever smokers (ptrend = 0.0010), men (ptrend = 0.0003), women (ptrend < 0.0001), and in shorter (ptrend = 0.0002) and longer (ptrend = 0.0001) duration of follow-up. There was no association between telomere length and risk of squamous cell carcinoma or other histological type of lung cancer in all or subgroups of individuals. The agreement of results from this prospective cohort study with those of previous prospective studies and Mendelian randomization studies suggest a possible etiological role of telomere length in the development of lung adenocarcinoma.

Stressful life events in early life and leukocyte telomere length in adulthood

Abstract Background Exposure to stressful life events (SLEs) in early life is associated with higher rates of morbidity and mortality from age-related chronic disease. In this study, we considered whether these general patterns extend to leukocyte telomere length (TL), an indicator of cellular aging. We also explored potential subgroup variations by race and age. Methods Using cross-sectional data from the Nashville Stress and Health Study (2011–2014), a probability sample of 1108 adults (558 blacks and 550 whites) ages 22–69, we tested whether SLEs experienced in early life were associated with shorter telomeres in adulthood. Leukocyte TL was measured using the monochrome multiplex quantitative polymerase chain reaction method with albumin as the single-copy reference sequence. An index of 32 potentially traumatic events experienced before the age of 18 was employed. An abbreviated index of seven events that are frequently used in telomere research was also employed. Results The complete SLEs index was unrelated to TL in the full sample (b = −0.003; p = 0.058) and for blacks (b = −0.003; p = 0.28), whites (b = −0.004; p = 0.18), and adults aged 45 or older (b = 0.001; p = 0.68). The complete SLEs index was inversely associated with telomere length (b = −0.007; p = 0.002) for those adults under the age of 45. Each additional SLE experienced before the age of 18 was associated with a reduction in TL equivalent to one additional year of age. The association between the complete SLEs index and TL for those under the age of 45 was statistically different from those aged 45 or older (t = 2.02; p = 0.04). In no case, was the abbreviated SLEs index related to TL. Conclusion This study confirms that the long-term health consequences of SLEs in early life can extend to shorter leukocyte telomeres in adults aged 22–44, but not adults aged 45–69. Our analyses also showed that the association between SLEs and TL is sensitive to the precise measurement of SLEs. We discuss the substantive and methodological implications of our findings for research on SLEs and cellular aging.

Lower mitochondrial DNA and altered mitochondrial fuel metabolism in HIV-exposed uninfected infants in Cameroon.

Evaluate blood mitochondrial DNA (mtDNA) content in HIV/antiretroviral-exposed uninfected (HEU) vs. HIV-unexposed uninfected (HUU) infants and investigate differences in mitochondrial-related metabolites by exposure group. We enrolled a prospective cohort of HIV-infected and HIV-uninfected pregnant woman/infant pairs in Cameroon. Dried blood spot mtDNA : nuclear DNA ratio was measured by monochrome multiplex quantitative polymerase chain reaction in HEU infants exposed to in-utero antiretrovirals and postnatal zidovudine (HEU-Z) or nevirapine (HEU-N), and in HUU infants at 6 weeks of life. Acylcarnitines and branch-chain amino acids (BCAAs) were measured via tandem mass spectrometry and consolidated into seven uncorrelated components using principal component analysis. Linear regression models were fit to assess the association between in-utero/postnatal HIV/antiretroviral exposure and infant mtDNA, adjusting for confounders and principal component analysis-derived acylcarnitine/BCAA component scores. Of 364 singleton infants, 38 were HEU-Z, 117 HEU-N, and 209 HUU. Mean mtDNA content was lowest in HEU-Z infants (140 vs. 160 in HEU-N vs. 174 in HUU, P = 0.004). After adjusting for confounders, HEU-Z infants remained at increased risk for lower mtDNA content compared with HUU infants (β: -4.46, P = 0.045), whereas HEU-N infants did not, compared with HUU infants (β: -1.68, P = 0.269. Furthermore, long-chain acylcarnitines were associated with lower (β: -2.35, P = 0.002) and short-chain and BCAA-related acylcarnitines were associated with higher (β: 2.96, P = 0.001) mtDNA content. Compared with HUU infants, HEU infants receiving postnatal zidovudine appear to be at increased risk for decreased blood mtDNA content which may be associated with altered mitochondrial fuel utilization in HEU-Z infants.

Evidence for a pre-existing telomere deficit in non-clonal hematopoietic stem cells in patients with acute myeloid leukemia

Telomere shortening represents an established mechanism connecting aging and cancer development. We sequentially analyzed telomere length (TL) of 49 acute myeloid leukemia (AML) patients at diagnosis (n=24), once they achieved complete cytological remission (CCR) and/or during refractory disease or relapse and after 1-year follow-up, with all patients having at least two sequential samples. TL was analyzed by monochrome multiplex quantitative polymerase chain reaction. We have observed substantially shortened TL in the cells of patients at diagnosis compared to age-adjusted controls. In patients reaching CCR after chemotherapy, telomere shortening was less pronounced than in persistence or relapse but still significantly shortened compared to controls. We estimate patients harboring approximately 20years of premature telomere loss compared to healthy aged-matched subjects at the time of AML onset. Our data indicate a pre-existing telomere deficit in non-clonal hematopoiesis of AML patients providing a link between age and AML development.

Telomere length and incident atrial fibrillation - data of the PREVEND cohort.

BackgroundThe incidence of atrial fibrillation (AF) increases with age. Telomere length is considered a marker of biological ageing. We investigated the association between leukocyte telomere length and incident AF in the Dutch Prevention of Renal and Vascular End-stage Disease (PREVEND) study.MethodsWe included 7775 individuals without prevalent AF, and with leukocyte telomere length measured. Mean telomere length was determined by a monochrome multiplex quantitative polymerase chain reaction-based assay.ResultsMean age of our cohort was 49±13 years, and 50% were men. During a mean follow-up of 11.4±2.9 years incident AF was detected in 367 (4.7%) individuals. Telomere length was shorter in individuals developing incident AF compared to those without AF (p = 0.013). Incident AF was inversely related to the telomere length. In the quartile with the longest telomere length 68 (3.5%) individuals developed AF, in the shortest telomere length quartile 100 (5.1%) individuals (p = 0.032). Telomere length was associated with incident AF in the second shortest telomere length quartile using the longest telomere length quartile as reference (hazard ratio 1.64; 95% CI 1.02–2.66; p = 0.043). After including age or AF risk factors, the relation between telomere length and incident AF was no longer significant. We found a significant interaction of age, male sex, systolic blood pressure, BMI, heart failure, and myocardial infarction with telomere length for the association with incident AF.ConclusionsWe found that shorter leukocyte telomere length is not independently associated with incident AF in a community-based cohort.

Telomere Length and Survival of Patients with Hepatocellular Carcinoma in the United States.

BackgroundTelomere shortening is an important molecular event in hepatocellular carcinoma (HCC) initiation; however, its role in HCC progression and prognosis is less clear. Our study aimed to examine the association of telomere length with survival of patients with HCC.MethodsWe measured telomere length in tumor and adjacent non-tumor tissues from 126 persons with HCC in the United States (U.S.) who were followed for mortality outcomes. Relative telomere length (RTL) was measured by a monochrome multiplex quantitative polymerase chain reaction assay. Multivariable Cox proportional hazards modeling was used to calculate hazard ratios (HRs) and 95% CIs for the association between telomere length and all-cause mortality. We also examined associations between telomere length and patient characteristics using multiple linear regression.ResultsDuring a mean follow-up of 6.0 years, 79 deaths occurred among 114 individuals for whom survival data were available. The ratio of RTL in tumor relative to non-tumor tissue was greater for individuals with regional or distant stage tumors (0.97) than localized stage tumors (0.77), and for individuals with grade III or IV tumors (0.95) than grade II (0.88) or grade I (0.67) tumors. An RTL ratio ≥1 was not associated with survival (HR 0.92, 95% CI 0.55, 1.55) compared to a ratio <1, after adjusting for age at diagnosis, sex, tumor stage and tumor size. Similarly, RTL in the tumor and non-tumor tissue, respectively, were not associated with survival.ConclusionsThis U.S. based study found that telomeres may be longer in more aggressive HCCs. There was no evidence, however, that telomere length was associated with survival of patients with HCC. Future investigations are warranted to clarify the role of telomere length in HCC prognosis.

Differences in placental telomere length suggest a link between racial disparities in birth outcomes and cellular aging

Health disparities begin early in life and persist across the life course. Despite current efforts, black women exhibit greater risk for pregnancy complications and negative perinatal outcomes compared with white women. The placenta, which is a complex multi-tissue organ, serves as the primary transducer of bidirectional information between the mother and fetus. Altered placental function is linked to multiple racially disparate pregnancy complications; however, little is known about racial differences in molecular factors within the placenta. Several pregnancy complications, which include preeclampsia and fetal growth restriction, exhibit racial disparities and are associated with shorter placental telomere length, which is an indicator of cellular stress and aging. Cellular senescence and telomere dynamics are linked to the molecular mechanisms that are associated with the onset of labor and parturition. Further, racial differences in telomere length are found in a range of different peripheral tissues. Together these factors suggest that exploration of racial differences in telomere length of the placenta may provide novel mechanistic insight into racial disparities in birth outcomes. This study examined whether telomere length measured in 4 distinct fetally derived tissues were significantly different between black and white women. The study had 2 hypotheses: (1) that telomere length that is measured in different placental tissue types would be correlated and (2) that across all sampled tissues telomere length would differ by race. In a prospective study, placental tissue samples were collected from the amnion, chorion, villus, and umbilical cord from black and white singleton pregnancies (N=46). Telomere length was determined with the use of monochrome multiplex quantitative real-time polymerase chain reaction in each placental tissue. Demographic and pregnancy-related data were also collected. Descriptive statistics characterized the sample overall and among black and white women separately. The overall impact of race was assessed by multilevel mixed-effects linear regression models that included empirically relevant covariates. Telomere length was correlated significantly across all placental tissues. Pairwise analyses of placental tissue telomere length revealed significantly longer telomere length in the amnion compared with the chorion (t=-2.06; P=.043). Overall telomere length measured in placenta samples from black mothers were significantly shorter than those from white mothers (β=-0.09; P=.04). Controlling for relevant maternal and infant characteristics strengthened the significance of the observed racial differences (β=-0.12; P=.02). Within tissue analyses revealed that the greatest difference by race was found in chorionic telomere length (t=-2.81; P=.007). These findings provide the first evidence of racial differences in placental telomere length. Telomere length was significantly shorter in placental samples from black mothers compared with white mothers. Given previous studies that have reported that telomere length, cellular senescence, and telomere dynamics are molecular factors that contribute to the rupture of the amniotic sac, onset of labor, and parturition, our findings of shorter telomere length in placentas from black mothers suggest that accelerated cellular aging across placental tissues may be relevant to the increased risk of preterm delivery in black pregnancies. Our results suggest that racial differences in cellular aging in the placenta contribute to the earliest roots of health disparities.

Acculturation Predicts Negative Affect and Shortened Telomere Length.

Chronic stress may accelerate cellular aging. Telomeres, protective "caps" at the end of chromosomes, modulate cellular aging and may be good biomarkers for the effects of chronic stress, including that associated with acculturation. The purpose of this analysis was to examine telomere length (TL) in acculturating Hispanic Mexican American women and to determine the associations among TL, acculturation, and psychological factors. As part of a larger cross-sectional study of 516 pregnant Hispanic Mexican American women, we analyzed DNA in blood samples ( N = 56) collected at 22-24 weeks gestation for TL as an exploratory measure using monochrome multiplex quantitative telomere polymerase chain reaction (PCR). We measured acculturation with the Acculturation Rating Scale for Mexican Americans, depression with the Beck Depression Inventory, discrimination with the Experiences of Discrimination Scale, and stress with the Perceived Stress Scale. TL was negatively moderately correlated with two variables of acculturation: Anglo orientation and greater acculturation-level scores. We combined these scores for a latent variable, acculturation, and we combined depression, stress, and discrimination scores in another latent variable, "negative affectivity." Acculturation and negative affectivity were bidirectionally correlated. Acculturation significantly negatively predicted TL. Using structural equation modeling, we found the model had an excellent fit with the root mean square error of approximation estimate = .0001, comparative fit index = 1.0, Tucker-Lewis index = 1.0, and standardized root mean square residual = .05. The negative effects of acculturation on the health of Hispanic women have been previously demonstrated. Findings from this analysis suggest a link between acculturation and TL, which may indicate accelerated cellular aging associated with overall poor health outcomes.